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Peterbilt 6x6 truck 1/24


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Hello model builders, 

 

Well, as things would have it, I started this project.  I wasn't planning on getting going for a while, but as I sat and watched my beloved San Francisco 49ers choke through and eventually lose today, I started building. 

 

A week or so ago I began seriously looking at info and doing some research on this project, which is to make a Peterbilt six wheel drive heavy or medium truck,  It will have a bed of some sort, rather than a 5th wheel, but I don't know what will be in that bed.  I prepared some images of what I'm planning to do.  First, please see some reference images of the prototype(s):

 

52450419285_975cf13d4b_b.jpg

 

So, a guy decided  to make something like one of these - and while not as mighty and majestic (😄) as a Kenworth 6x6 oil field truck, I think these examples are just fine, and I like the looks of Peterbilts.   But, as no such kit exists, I'll need to scratch and kitbash my way through.  Note the height difference between the Peterbilt 365 in the upper left, compared to the conventional tractors next to it!

 

I have an 1/24 scale Peterbilt 378, which is a a long-haul highway tractor - not an off-road rig - at all.  But, it is what I have, so I prepare this little study:

 

52450419280_883a128413_b.jpg

 

And short of reciting all of those points, what you will find is that the current Peterbilt truck (the 367) would be really hard for me to achieve - I really pondered giving it a go, but just don't think I can (as noted above, there are several BIG differences with my donor kit), which is a bummer because I really like the looks of that truck.  This leads me to the older 3 series tractors, which share the same (basically the same or similar to) the 378.  The 365 is a heavy duty brute - but, for a build, it might not be all that challenging (for the bodywork) so, I'm opting for a 382 or 348 - which have the same hood, but different engine.

 

Key to the build is the front axle:

 

52450419275_548b0226dd_b.jpg

 

As shown above, the truck I'm modeling will have a solid front drive axle - the lower two images are of a 348, while the upper two from a 365.  For this, I'm starting with a KFS axle, but I'll scratch the leaf springs and suspension.  Also, note the single tires on the rear axles on the 348 in the lower left corner - I'll use singles too.

 

For the rear end, well, something completely new to me.  Below you'll see a Hendrickson walking beam tandem rear suspension - but, note no air bags or leaf springs - just rubber pads at a pivot point.   

While new to me, this has evidently been around a while - and is well suited for rough terrain and a good candidate for some scratch work!:

 

52450491628_942752d0ea_b.jpg

 

Hopefully these images are understandable - the "walking beams" are a pair of solid arms, on each side of the chassis, that are connected to the axles.  There are bushings where they tie to the axles, so there is rotation and the beams pivot from a central point where they mount to the chassis of the truck.  So, I'm going to try and build them.  I have two KFS axles, which, aside from being for a heavy duty tandem, are almost exactly unlike the setup!  a good challenge!

 

As noted above, I was not planning to do anything on this for a while.  But, as the game was depressing, I did - and started the hood:

 

52450419260_35d6e4a973_b.jpg

 

I built a Pete 348 once before, but from a different donor kit.  In this kit, as you can see in image 1, you get a one piece hood with fenders.  So, while trying to ignore the demise of my 49ers, I got to thinking about how to convert this hood.  Step one, I left it and it's chunky connecting points on the sprue, to assure some degree of alignment stability for what I was about to do.  Last time I bult the whole thing from scratch - a lot of complicated work. 

 

This time, a conversion.  The Tamiya tape (figure 1) is my cut line - as the 348/382 hood slopes and as you can see, the 378 doesn't.  But, before cutting it apart, I built front and rear frames, to support what I planned to be a scratch built cover (figure 2) .  Turns out though, that I could modify the part I cut off and reset it (figure 3)  what a surprise!  And below, you can see how it turned out:

 

52450419250_a1da2fd0eb_z.jpg

 

It now has a slope!  While not easy, this relied on visual comparisons to photos, and not a rigorous analysis, primarily because I wasn't planning to start this as soon as I did.  Turns out, it was a LOT easier than scratch building all of it.

 

That said, it worked out pretty well:

 

52450419230_3234852b5a_c.jpg

 

Above, you can see a cutout of the hood comparing it to a 382.   Note:  I didn't forget the concentric design on the fenders!  just haven't start them yet,  and below:

 

52450419235_0b21d34c3b_b.jpg

 

The hood is superimposed on the truck on the left - the base images is of a 348.

 

So, we're off.  No building this week tho.  Work will have me tied up, so maybe back at it next weekend.

 

Thanks for having a look - 

 

Cheers

Nick 

 

 

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Hi Model  builders, 

 

Jeroen, I thought you might like this one, as you too like making the big rigs!

 

Not too much to share, but I have made some progress on the hood.  First up, some framing:

 

52466116055_71d578c4e8_b.jpg

 

 

Unhappily, there is not much contrast in these photos, but hoping you can make out that I added some styrene to get the basis for the bigger fenders found on these tractors - And yes, I eliminated the flat spot on the arc in the image on the upper left.  What you can also see is a .025" segment of rod which curves along the side of the hood side.  This is used to mount the thin sheet used to make the fender inner arc.  It turns out the overall form of the top of the fender is concentric, so the kit parts are modified to achieve the right look:

 

52466116050_c90376c6e5_b.jpg

 

Again, unhappily, there is not much contrast evident, but you can see the fenders taking shape.  There is a sheet of .010" sheet laid over the previously shown frame work.

I've added putty and will sand to get a uniform surface.  

 

As the hood and cab don't have a uniform base height (ie I've tried to "test" tilt, but can't really achieve the alignment/movement), I am not sure of exactly how the hood will tilt without hitting the cab?  But, I did angle outward the edges of the fender framing, to allow for some clearance - we'll see....

 

Next up, the frame and suspension.  I'm using an old set of KFS laser cut styrene channel to make this.  I'm not sure of how long to make it but, will figure something out.  Then, will start with the front leaf spring packs and axle.  With that built, I'll be able to set the rear suspension height.

 

Thanks for having a look - 

Cheers

Nick 

 

 

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So, back at the shop I'm still playing Billy big rig! 😄  "Real" work was slow for the last few days, so deeper into this I went. 

 

Hi Jeroen, I appreciate your optimism! They are coming together.  I find I have to be really careful with restraint, that is, to know when to stop sanding, if it is "exactly"  right or not - lol

 

Hi Vesa, appreciate it!  It's also turning into some serious head scratching - -  🤨 😄

 

Hi Houston, well, thanks very much!  I also appreciate your optimism, will be useful as we keep after it!

 

Hi Andy, appreciate that comment, but - you know - you think it's just right - and alas, well, it's not - lol - I can live with it!  

 

First up, I walked out for lunch about an hour ago, and this happened:

 

52475779833_2837aaa77d_b.jpg

 

A nice comparison of two different Peterbilt tractors!  the key differences being the hood and fenders - I am trying to do something like the red version - Looking at this, and thinking about the comments above, I don't think my fenders have enough swoop/big curve high on the side of hood sides - again, I'll live with it! - or not, maybe keep adding to the fenders?  not sure just yet.

 

But, other areas are coming along - first up, the front spring pack and attachment to the axle:

 

52475697955_c0c87786e8_b.jpg

 

As you can see - lots of different materials going into this - the springs look tiny compared to the tires and axle, but are about 50" (scale) inches long! and that's 7 leafs!  if will ride like an ox-cart!

 

52475233781_35e9f1ddb1_c.jpg

 

And - what to do about the chassis?  The chassis is the laser cut kit from KFS - and you can see the black kit chassis in the foreground.  This is turning into a big model!!  I went with the shorter version - only because it's shorter and I might be able to get it to sit nicely on a shelf somewhere when it's done.

 

52475514409_bef0ffdf48_b.jpg

 

So - this suspension, is a challenge.  The axle leaf pads are just wider than the chassis rails, so the brackets are mounted projecting from the chassis - but, hidden within is a cross member to mount the engine near the oil pan, and the engine mounts toward the bell housing, need to be slightly lifted inside the frame rail to work. Getting this more or less correct will allow the cab to fit, and the hood to tilt.   The kit includes a giant CAT engine, and huge radiator.  The truck I'm building uses a smaller Paccar engine...and different radiator.  So - nothing fits as is.  Also, the hood hinges are mounted on the outermost part of the horns, above the front leaf spring hangers.....good times.   As you can see the engine is only taped in, and I'll need to modify the kit fan, make a new shroud, and save what I can of the radiator.

 

52475514389_984a2135b8_b.jpg

 

But, it works!  happily for me, the front axle is indeed centered on the fender well opening!

 

52475233756_e9cc6a1ac0_b.jpg

 

 

I shot these two for scale - this is a big model - long and tall.

 

With the front end installed - less steering etc, I decided it was time to start thinking about the rear end - challenge 1, axle width.....:

 

52475514379_63b39da4c3_b.jpg

 

And above, the lower axle is the front with leaf springs attached, and the upper, the rear axle on the left you can see the tires I'm using - and the hubs required, but, they don't fit and are too narrow on the axle.  In the upper right, well, the axle and hubs that fit - but, of course, don't fit the wheel.  So, these will be spliced together, and the obvious goal, to get the front and rear axle/wheels to be about the same width.  Then to get after the walking beam suspension.  

 

Ok, that's all for today - thanks for having a look and happy model building,

 

Cheers

Nick 

 

 

 

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Hello model builders,

 

Billy big rig here again - I simply could not abide those fenders.  So, a guy went ahead and changed them:

 

52476120824_2b4e448ae7_c.jpg

 

So the first step was to figure out what was wrong - the outer curve was thin, and the inner, sitting too low on the hood side. So, as you can see above, went about fixing these.  Next, adding a new outer shell:

 

52475340627_d5123a55b3_c.jpg

 

And now, slightly more credible fenders!  The "skin" is very thin, at .010" - so, touching it up with some Tamiya white putty - which unhappily is a bit dried out, so not all that user friendly.  However, in the end - better than where we were.  

 

OK, I feel better now- 

 

Cheers

Nick  

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Usually, a guy does the right thing, and pretends he didn't see that, but I can see why you weren't happy with those fenders. They do look beefier now. Nice work on those axles too, that's always a challenge.

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Hi Jeroen, ha! yes, we are speaking the same language - I simply could not pretend not to see -- 😄

 

So, this is how they turned out:

 

52480639775_06a6575c9c_b.jpg

 

"a guy" simply couldn't abide the other version! 😄  these still need some sanding, but they are better!

 

Now, back to Billy big rig - and the rear suspension.  My plan was to convert a KFS rear end that seemed close - and well in concept, it is close, but in application, and with big tires, not good:

 

52480639770_cfd36c0961_c.jpg

 

Well, not ideal - the tandem tires are too close, so, I extended the KFS control arms, and experimented with length until it looked right:

 

52480453214_036cc72b71_c.jpg

 

Hmm - as you can see in the red circle, the kit control arms are too short, so I lengthened them - first too much, then cut them back - the photo on the right is not correct.  I cut 2mm off each and they worked ok.  Then on to the walking beams:

 

52480722858_e03a5400c4_b.jpg

 

As I didn't have walking beams, a guy went ahead and made them. I have a nice diagram of what these are supposed to look like, so laminated several sheets of cut .040" styrene together to make them. It's 62 mm from centerline of bushing to centerline of bushing for this model.  A bit slow going but more or less correct. I might beef them up as we go, as they just look thin.  That said, they work.  And as to why I chose this suspension:

 

52480722848_892cbf369c_b.jpg

 

You can see plenty of flex.  But, next up will be making the bracket to hang this from the chassis.  Which brings to light two problems - I think I can keep the dramatic pivot using some extra brass clevis connections I have - but, as both of these are drive axles, I'll need to make some flex on the driveline too.   A while ago I purchased several small scale u-joints, intended for RC kits - which might work here - don't know just yet!

 

OK, thanks for having a look - 

 

Cheers

Nick  

 

 

 

 

 

 

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Hello model builders,

 

@JeroenS and @keefr22 - how about those ti/yres!! yes, they are pretty hefty!  As always I really like KFS products.  These were a bit uncharacteristically chunky, so they received some attention from the sanding block, to round off the edges and level out the tread.

 

@Vesa Jussila, yes, there is plenty of scratch work here, and I must say that includes lots of head scratching!  While the KFS axles are in use, I wound up adding new tabs for the walking beams and cutting off the others, which is fair enough, as this rear end was supposed to be used for another kit - 🤨 😄

 

Well, my beloved SF 49ers didn't play today, so I kept after this truck.  I spent all day working on two brackets!  How hard could that be? well, maybe not all that hard, but certainly slow going.  Nonetheless, after building and tearing apart a few times, some progress was made:

 

52482814919_6b27c49576_c.jpg

 

While new to me, this suspension has apparently been in use for quite a while, so with some effort I was able to find photos and even some diagrams.   But, as none of these are dimensioned, I took a different approach to getting the dimensions that would result in a flat chassis.  Basically, propping the rear end up to match the front with tires and wheels in place, then measuring the gap between the top of the walking beam and the bottom of the chassis rail, then adding the thickness of the chassis and walking beam.  You can see the layout in the lower left above.  Next, I measured the length of the clevis' I'm using to allow this to pivot (the square space you see on the two images to the right.  It turns out the bracket is mounted on the outside, then filled to match the thickness of the walking beam.  Sorry if that was to windy an explanation - hopefully the pic in the upper left clarifies this. 

 

Oh - you'll also note those fancy pants U-joints.  Well...they're in - but they put up quite a fight - both in terms of adapting them to driveshaft and pinions, and in getting the length to work and not fall out!  There is a slip joint to allow flex, but it turns out, the geometry of the two trailing/control arms affects the geometry of the driveshaft, and alignment of the entire rear end - how do I know that?  see below:

 

52483091103_80bfd56b74_c.jpg

 

Ahh, more model building good times....as you can maybe see in the photo on the right, the walking beams are not parallel to the chassis rails!  And the driveshaft fell out each time I tried to make this work.  Why???!!  well, I measures all of it for square - check - so why???  The front trailing arm was about a millimeter longer than the rear.  Obviously 😄  So, out it came, and I cut it down and made a sleeve, like a slip joint yoke and that seemed to do the trick:

 

52483008225_5b7f188359_c.jpg

As you can see, it now sits level.  I still have to add lots of detail to those brackets, like the diagram, but at least the overall system seems to work.  Sort of funny, took a few minutes to type this up, and all afternoon to make it work 😄  And below, it still flexes.  I came very close to giving up on this - as the driveshaft dropped repeatedly, and only the rear end would only tilt upward on the forward side - annoying:

 

52482814904_8930119cd5_c.jpg

 

And above, you can see, it still tilts and flexes.

 

So, a productive weekend, thanks for having a look

 

Cheers

Nick   

 

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I like the look of what you're doing here Nick, though from memory the Hendrickson rubber block suspension was more highway than off rood, I seem to recall it was a bit limited in articulation, but stand to be corrected on that, it'll look the goods anyway.

Steve.

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Nice work on the tandem again, I can see why that would be a challenge. Where did you get those fancy U joints? Did you mention it in the thread, and I missed it? If so, sorry for asking 🙂 

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Hello guys, 

 

@stevehnz, hi Steve, you could well be right!  I am hardly a big truck expert, but do enjoy building models of them.  As I was getting going on this, I did some homework, but hardly scientific or through - and along the way, I found this image from Hendrickson that caught my eye.  It's unclear to me how they achieve this much flex with the rubber blocks - adding to this, I have since seen several concrete mixers with this in use, which don't suggest something with too much flex 🤨

 

52483967681_b95dfbc139_c.jpg

 

This is the prototype I'm going for.  Now that I have been working on this for a while, It seems the rubber blocks themselves don't "give" too much, but because the bracket and axles have pivot points, some flex may be achievable.  I really don't know!  I appreciate you taking some time to join the discussion - as it seems you know about trucks, please keep sharing some thoughts on this!  I don't want to make any giant blunders as we go!

 

@JeroenS, Hi Jeroen, the u-joints are some no-name variety I found on Ebay.  They are intended for use on RC vehicles, and while a bit out of scale, heck, they are fun to use and were not expensive!  They use tiny allen studs, and it turns out the wrench for these is more expensive than the u-joints.  I didn't buy the wrench, and instead used a fine point, magnetic phillips head screw driver, then sealed with some CA, a bit like locktite!

 

Cheers

Nick 

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2 hours ago, Stickframe said:

hi Steve, you could well be right! 

It doesn't come with a guarantee. I'm casting my mind back to when this system was quite new & as I recall, not necessarily reliably, it was one of the criticism of it. I think Foden, after it was bought out by Paccar & became a badged Kenworth, used this in a light chassis for mixers & site trucks so it must have been up for it I guess.

Steve.

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Well guys, sort of a funny day - did some zoom calls, emails, and so on for "real" work, and had more time than I guessed for the big Pete -  Speaking of "big Pete" - man, that breakfast sounds pretty good!  I might just walk on down to my neighborhood cafe in the morning and go for some pancakes and coffee!! 😄  It could be a treat - supposed to rain all night - a good reason to break out the umbrella and go for a stroll!

 

And back to serious business,  I kept going on the rear end.  During this phase of work, the tasks ranged from getting it to work ,to getting it to look right - both important, but as it's only a model, both required some head scratching.  As you all know, there are limitations that come from scale - you can't "just" do anything as the parts are small and there are not scale welders, grinders, cutoff tools, ratchet straps, or ratchet wrenches - instead, giant fingers, huge knives, lots of Tamiya tape, sanding sticks, glue, optimism and enthusiasm 😄

 

In the spirit of this, on we went with that sassy Hendrickson rear end:

 

52485926070_6df2393156_b.jpg

 

Sheesh - there is plenty going on here - I finally figured out the right geometry between the walking beams, drive shafts, brackets, and control/pivot arms from each diff to the chassis cross member.  I wish I could report that I came across some clear and logical answer or keen insight, but - no, just an instinct to declare that it was done.  This "inspired" conclusion was driven by the reality that this is indeed a model being built with no instructions, dimensions, or "replacement" parts - time to hope for the best. 

 

With that declaration made, it was time to figure out how to make it look right - the relatively easy part was adding nuts and bolts - a bit tense, but not too hard to do.  The bigger challenge, as noted by @stevehnz, was getting the required rubber blocks in place.  To clarify this, as you can see above, in the area circled in red, this suspension (should) include rubber blocks between two steel parts - but, a guy doesn't have those handy.....what to do??  After a fair amount of pondering, we came up with the idea that rather than installing a solid piece of material between the two plates, two opposing parts would be installed.  That is, two thin pieces of styrene, on the top and bottom, that don't align with one another would be glued in place.  This would allow the appearance of a solid surface, but as the two parts are offset from each other, the walking beam could tilt, and  suspension could move! Well, I was pretty happy with this idea! Next step will be to add some really thin styrene  rods to the plates to make them look more convincing.  

 

Another minty treat was adding the "Transverse Torque Rods"....yeah - the two rods that extend from the axle to the chassis.  Happily, the KFS kit had some rods - not intended for this exactly, but I can adapt.  As you can see above, a guy installed some alu square tube to the axle, then attached said "Rods" to the axle brackets, and eventually connected them to the chassis.

 

And installed:

 

52486007623_5f4329131f_b.jpg

 

I wish I could report that installing this was easy and went smoothly - it wasn't and it didn't 😄  The common model builder's lament - if I had another hand or two, but like each of you, on we went.   Once the basic assembly was in place, went ahead and built some receiving brackets for the torque rods, attached them to the rods from the axles/diffs, and glued them in place.  The biggest surprise was that it still flexes - not quite as much as before, but pretty fine with me.  In the morning I'll add (fake) torque rods, front and back (in the area with the red circle.

 

Ok, time to go to bed - those pancakes are on my mind - lol -

 

thanks for having a look

 

cheers

Nick 

 

 

 

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9 hours ago, Stickframe said:

I might just walk on down to my neighborhood cafe in the morning and go for some pancakes and coffee!! 

Hold the Maple syrup. Can't stand the stuff. Honey and or Blueberry jam (jelly). Healthy! Oh, and coffee, black as it comes. Enjoy!

Fabulous work on the rear suspension. It looks so complicated, and it works. Full marks for patience and skill.

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